Synthesis of spiro-1,2-dioxolanes and their activity against Plasmodium falciparum

Artemisinin-derived compounds play an integral role in current malaria chemotherapy. Given the virtual certainty of emerging resistance, we have investigated spiro-1,2-dioxolanes as an alternative scaffold. The endoperoxide functionality was generated by the SnCl4-mediated annulation of a bis-silylperoxide and an alkene. The first set of eight analogs gave EC50 values of 50–150 nM against Plasmodium falciparum 3D7 and Dd2 strains, except for the carboxylic acid analog. A second series, synthesized by coupling a spiro-1,2-dioxolane carboxylic acid to four separate amines, afforded the most potent compound (EC50 not, vert, similar5 nM).